Yes, inquiring mines want to know. Me too. I sure like the looks of the home made reflector with two horizontal bulbs. Am going to make one. Before I saw his video, I bought a four bulb vanity bar from E-bay. So I can go either way.
Kenny

Unless you are trying to grow only a couple of plants, I would go with horizontal. But if it is one or two plants in a small hydro unit or similar, I would go vertical and buy one of those cheap cylindrical reflectors.